Celsius to Kelvin Converter
Convert Celsius to Kelvin and back. K = C + 273.15.
Tip: Results show up to 8 significant digits. The factors and their sources are listed on the "Where our numbers come from" page.
On this page
Celsius and Kelvin
Celsius and Kelvin are two ways to measure the same temperature, related by the formula K = C + 273.15. The converter works both ways: use the two tabs at the top of the tool to choose the direction.
Quick conversion table
Celsius to Kelvin
| Celsius | Kelvin |
|---|---|
| -273.15 °C | 0 K |
| -100 °C | 173.15 K |
| -40 °C | 233.15 K |
| 0 °C | 273.15 K |
| 10 °C | 283.15 K |
| 20 °C | 293.15 K |
| 25 °C | 298.15 K |
| 37 °C | 310.15 K |
| 100 °C | 373.15 K |
| 1,000 °C | 1,273.15 K |
Kelvin to Celsius
| Kelvin | Celsius |
|---|---|
| 0 K | -273.15 °C |
| 100 K | -173.15 °C |
| 200 K | -73.15 °C |
| 273.15 K | 0 °C |
| 293.15 K | 20 °C |
| 300 K | 26.85 °C |
| 373.15 K | 100 °C |
| 500 K | 226.85 °C |
| 1,000 K | 726.85 °C |
Exact factor and source
| Conversion | Formula | Basis |
|---|---|---|
| Celsius to Kelvin | K = C + 273.15 | SI Brochure, 9th edition (BIPM 2019): degree Celsius, defined from the kelvin (0 C = 273.15 K) |
| Kelvin to Celsius | C = K - 273.15 | SI Brochure, 9th edition (BIPM 2019): SI base unit of thermodynamic temperature; 0 C = 273.15 K |
How to convert degrees Celsius to kelvins
- Step oneTake the temperature in degrees Celsius.
- Step twoAdd 273.15.
- Step threeThe result is the temperature in kelvins. To go back, subtract 273.15.
Example: 25 C + 273.15 = 298.15 K.
All temperature units compared
Each unit written in degrees Celsius, the base unit of this tool. Exact values come straight from the definitions.
| Unit | Symbol | Relation to Celsius |
|---|---|---|
| Degrees Celsius | °C | base unit |
| Degrees Fahrenheit | °F | C = (F - 32) x 5/9 |
| Kelvins | K | C = K - 273.15 |
What is Celsius?
Celsius sets 0 degrees at the freezing point of water and 100 degrees at its boiling point at standard pressure. Most countries use it for weather and cooking.
What is Kelvin?
Kelvin (K) is the SI unit of temperature. Zero kelvin is absolute zero, and 0 degrees Celsius is 273.15 K. A change of one kelvin equals a change of one degree Celsius.
What this converter does not do
- Results are rounded for display to 8 significant digits; the stored factor is the exact one.
- It converts a temperature reading. A temperature difference converts differently: a change of 10 degrees Celsius is a change of 18 degrees Fahrenheit.
- It does not account for pressure, altitude or the boiling point of any liquid.
Frequently asked questions
What are 0 and 100 degrees Celsius in kelvins?
0 °C is 273.15 K, and 100 °C is 373.15 K. The two scales are related by a formula, K = C + 273.15, not by a single factor.
What are 0 and 100 kelvins in degrees Celsius?
0 K is -273.15 °C, and 100 K is -173.15 °C. Use the other tab of the converter to go in this direction.
What is absolute zero in Celsius?
Absolute zero is 0 kelvin, which is -273.15 degrees Celsius.
Where do the factors come from?
Degrees Celsius: SI Brochure, 9th edition (BIPM 2019): degree Celsius, defined from the kelvin (0 C = 273.15 K). Kelvins: SI Brochure, 9th edition (BIPM 2019): SI base unit of thermodynamic temperature; 0 C = 273.15 K.
References
- Celsius: SI Brochure, 9th edition (BIPM 2019): degree Celsius, defined from the kelvin (0 C = 273.15 K)
- Kelvin: SI Brochure, 9th edition (BIPM 2019): SI base unit of thermodynamic temperature; 0 C = 273.15 K
- NIST Special Publication 811: Guide for the Use of the International System of Units (SI), 2008 edition.
- The International System of Units (SI Brochure), 9th edition, BIPM.